Draft appliance.



No. 825,776. PATE-N'I'ED JULY 10, 1906.

C.-M. THOMPSON. DRAFT APPLIANCE.

APPLICATION II-LED OCT. @1905.

Quoewkoz ClarktmnMjhom ason PATENT OFFICE.

OLARKSON M. THOMPSON, OF PORTLAND, MAINE.

DRAFT APPLIANCE.

Application filed October 7.1905- Serial No. 281,805.

To all lUhOTIb it may concern:

Be it known that I, CLARKSON M. THOMP- SON, a citizen of the UnitedStates of America, residing at Portland, in the county of 5 Cumberlandand State of Maine,have invented new and useful Improvements in DraftAppliances, of which the following is a specification.

This invention relates to draft appliances 1 designed especially for usein connection with steam-boiler furnaces, and has for its object toproduce a comparatively simple inexpensive device of this characterwhich may be readily installed for use, one wherein a forced I draftwill be induced in the boiler-furnace, one in which the draft will beautomatically controlled to accord with the steam-pressure in theboiler, and one in which the draft may be entirely cut off whencircumstances require.

With these and other objects in view the invention comprises the novelfeatures of construction and combination of parts more fully hereinafterdescribed.

2 5 In the accompanying drawings, Figure 1 is a front elevation of afurnace equippe with a draft appliance embodying the invention. Fig. 2is a section, on an enlarged scale, taken on the line 2 2 of Fig. 1.Fig. 3 is an inner face view of the steam-injecting device.

Referring to the drawings, 1 designates a furnace of-the usual or anyappro riate construction having a door 2 for c osing the 3 5 mouth ofthe ash-pit 3, which forms a part of the combustion-chamber, these partsbeing designed to perform their ordinary functions.

Secured at its forward end in the door 2 and projecting into theash-chamber is a tubular inwardly-tapered draft member or bell 4,'having an enlarged mouth 5, in which is fixed an injector device 6,preferably comprising a plurality of circular coils or sections 7 ofpipe-tubing, provided at their inner faces with jetopenings 8 andconnected for communication one with another by means of tubularcoupling members or elbows 9, it being noted that the coils or sections7, which are spaced apart in a direction longitudinally of the bell 4,are of relatively decreasing sizes from the front to the innermost coil.

Connected at one end with the outer and largest coil 7 is a pipe sectionor duct 10, having its other end connected by a swivel-coupling 11 withthe lower end of a steam pipe or Specification of Letters Patent.

Patented July 10, 1906 duct 12, leading from the engine-boiler, (notshown,) and provided at a suitable point between its ends with a cut-offvalve 13, the stem 14 of which is pivoted to an 'operation lever 15, inturn connected by a chain or 6 other suitable flexible element 16 withan automatic pressure-regulator 19, adapted to be controlled by thepressure in the boiler, there being arranged on the lever 15 a weight16, tending to hold the parts in normal posi tion with the valve open.

Rotatively mounted in the draft member or hell 4 at a point adjacent theinner end of the latter is a cut-off member or dam er 17, to which isconnected an operating e ement or chain 18, extending outward throughthe mouth 5 of the bell.

In practice when the valve 14 is open steam passes through pipes 12 and10 into the coils 7 of the injector, from which it is in- 7 5 jectedthrough the jet-openings 8 into the ash-pit, serving at the same time todraw air into the latter through the draft bell or funnel 4, it beingmentioned in this connection that owing to the peculiar arrangement of8c the inj ector-section 7, as heretofore explained,

a greater force is given to the injected steam and a freer entrance ofthe air into the bell is permitted. When the pressure in the boiler hasreached the normal degree, the valve 13 is'automatically operated, owingto its communication with the pressure-regulator, for closing the pipe12 and cutting off the supply of steam to the injector. As soon,however,

as the pressure drops below the normal in the boiler the valve 13 isautomatically opened by means of the weight 16, thereby opening the pipeto permit entrance of steam to the injector for operation, as beforeexplained.

It is to be noted that the coupling 11 is ar 5 ranged in axial alinementwith the hinges of the door, whereby the latter may be readily openedwhen circumstances re uire and, further, that under the action of theinjector 6 an induced draft is maintained in the combustion-chamber,thus insuring perfect combustion and minimizing the amount of smokegenerated by the burning fuel.

From the foregoing it is apparent that I roduce a simple deviceadmirably adapted for the attainment of the ends in view, it beingunderstood that in attaining these ends minor changes in the detailsherein set forth may be resorted to without departing from the spirit ofthe invention. 1 1o member, said device comprising a plurality ofdistinct sections or coils of relatively vary- .ing sizes spaced apartin a direction longitudinally of the member and with the smaller sectioninnermost, tubular couplings connecting the sections for communicationone with another, a steam-duct communicating with the injector device,and means controlled by the pressure in the boiler for automatically Icontrolling the supply of steam to the injector. 2. In a device of theclass described and in combination with a boiler-furnace having acombustion-chamber, of a tubular draft 20 member communicating with thelatter, an injector device disposed in the draft member, said devicecomprising a plurality of sections or coils connected for communicationone with another, a steam-duct leading from the boiler to one of thecoils for supplying steam thereto, a cut-off valve arranged in the duct,a weighted lever connected with said valve and adapted for maintainingthe same normally in open condition, and means controlled by anincreased pressure in the boiler for operating the lever to close thevalve.

In testimony whereof I aflix my signature in presence of two witnesses.

CLARKSON M. THOMPSON. Witnesses Jos. B. SHEPHERD, WILLIAM F. LONG.

